* {
    margin: 0;
    padding: 0;
}

header, .main, .main_informationDisplay>div {
    padding: 20px;
}

header {
    background-color: rgb(53, 138, 136);
    color: #fff;
    letter-spacing: 5px;
}

.main {
    display: flex;
}

.main_menu:hover {
    cursor: pointer;
}

.main_informationDisplay {
    display: flex;
    flex-grow: 1;
    margin-left: 20px;
}

.main_informationDisplay>div {
    flex-grow: 1;
    border-width: 2px;
    border-style: solid;
    border-color: transparent;
}

table, th, td {
    border: 1px solid #ccc;
}

table {
    width: 100%;
}

.studentsList>caption {
    font: 1.17em bolder;
}


/* h2 样式 */

.main_menu {
    padding: 10px 20px;
    background-color: rgb(32, 82, 80);
    margin-bottom: 4px;
    color: rgb(53, 138, 136);
}


/* 效果 */

.menu_checked {
    background-color: rgb(53, 138, 136);
    color: #fff;
}

.main_informationDisplay_checked {
    border-color: #006363 !important;
}